#include <stdio.h>
#include <stdlib.h>

int main()
{
    int a = 0;
    int b = 1;

    int *p = &a;
    int **pp = &p;

    **pp = 2;
    *pp = &b;
    *p = 3;
    printf("a = %d,b = %d\n",a,b);
    return 0;
}
